Rarotonga, New Zealand Photograph by Diana Morshead   Pacific Ocean: Cook Islands Tropical and Subtropical Moist Broadleaf Forests   100 square miles (200 square kilometers) -- about the size of Washington DC Critical/Endangered

· Island Introductions
· Special Features
· Did You Know?
· Wild Side
· Cause for Concern
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Island Introductions

If you sailed a ship from Hawaii south across the Pacific Ocean, you'd be about halfway to Antarctica before you reached the southern Cook Islands. These tropical islands may seem extremely isolated. But in fact they've been inhabited by people for hundreds of years--first settled by Polynesians and later by Europeans. For that reason, the native biodiversity of these islands has long been altered by the activities of humans and by the introduction of plants and animals from distant lands.

Special Features

Temperatures are generally mild and rainfall relatively abundant on these tropical islands, with November and December being the wettest months. The ecoregion comprises nine main islands. The largest and highest of the islands, Rarotonga, is a long-extinct volcanic cone with steep slopes. Its upper slopes feature some of the best remaining examples of primary montane rain forest and cloud forest in Eastern Polynesia. Aitutake Island is called an "almost-atoll" because it consists of a central volcanic island surrounded by a barrier reef. Miti'aro, Atiu, Ma'uke, and Mangaia are the remains of ancient volcanoes. Some islands are flat reefs that cap old volcanoes and were raised above sea level.

	Within about 100 years, the introduced African ant caused the extinction of 11 of the 13 endemic snails on Rarotonga Island.

Wild Side

Climb the slopes of these islands and you'll find two kinds of montane rain forest and a cloud forest. Lianas, mosses, and ferns grow on and around the dominant trees. Four birds are found on these islands and nowhere else: Rarotonga starlings, Mangaia kingfishers, Rarotonga monarchs, and Atiu swiftlets, which breed in caves. Tonga flying foxes, a kind of bat, fly through the forests at night. Many species of snails creep up and down the forest plants. And about 130 native plants grow in this region.

Cause for Concern

Native vegetation in the lowland portions of the southern Cook Islands was removed long ago to make way for coconut palm plantations and other crops. But the upper elevation forests of this ecoregion are relatively intact. Their greatest threat comes from introduced species. For example, Rarotonga monarchs numbered only 29 in 1989 because introduced black rats were preying heavily on their eggs and young. Control of rats helped the birds' population bounce back to 100 by 1995. Other introduced species causing problems include common myna birds, cats, and African ants.

For more information on this ecoregion, go to the World Wildlife Fund Scientific Report.